Sashelp Data Sets

Tropical Rain Forest Tree Data

The Sashelp.BEI data set contains the locations of 3,604 trees in a number of tropical rain forests (Condit 1998; Hubbell and Foster 1983; Condit, Hubbell, and Foster 1996). A study window of 1,000 $\times$ 500 square kilometers is used. The data set also contains covariates, represented by the variables Gradient and Elevation, which were collected at over 20,301 locations on a regular grid across the study region. The variable Trees distinguishes the event observations in the data set. The following steps display information about the data set Sashelp.BEI and create Figure B.2:

title 'BEI Data';
proc contents data=sashelp.bei varnum;
   ods select position;
run;

title 'The First Five Observations Out of 23,905';
proc print data=sashelp.bei(obs=5);
run;

title 'The Trees Variable';
proc freq data=sashelp.bei;
   tables Trees;
run;

Figure B.2: Tropical Rain Forest Tree Data

BEI Data

Variables in Creation Order
#	Variable	Type	Len
1	X	Num	8
2	Y	Num	8
3	Elevation	Num	8
4	Gradient	Num	8
5	Aluminum	Num	8
6	Boron	Num	8
7	Calcium	Num	8
8	Copper	Num	8
9	Iron	Num	8
10	Potassium	Num	8
11	Magnesium	Num	8
12	Manganese	Num	8
13	Sodium	Num	8
14	Phosphorus	Num	8
15	Sulphur	Num	8
16	Zinc	Num	8
17	Ammonia	Num	8
18	Nitrate	Num	8
19	TotalNitro	Num	8
20	MinAmmonia	Num	8
21	MinNitrate	Num	8
22	MinNitrogen	Num	8
23	pH	Num	8
24	Trees	Num	8

The First Five Observations Out of 23,905

Obs	X	Y	Elevation	Gradient	Aluminum	Boron	Calcium	Copper	Iron	Potassium	Magnesium	Manganese	Sodium	Phosphorus	Sulphur	Zinc	Ammonia	Nitrate	TotalNitro	MinAmmonia	MinNitrate	MinNitrogen	pH	Trees
1	11.7	151.1	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	1
2	998.9	430.5	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	1
3	980.1	433.5	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	1
4	986.5	425.8	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	1
5	944.1	415.1	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	.	1

The Trees Variable

Trees	Frequency	Percent	Cumulative Frequency	Cumulative Percent
0	20601	85.11	20601	85.11
1	3604	14.89	24205	100.00